Apparatus for loosening thread protectors from tubular bodies

ABSTRACT

An apparatus for removing substantially hollow articles from other articles into which or around which they are clamped, the article to be removed being mainly symmetrical around an axis and the surface of the other article to which it is clamped also being symmetrical with respect to an axis so that the removing is mainly possible by rotation. The apparatus comprises a rod with two lugs at a distance from each other along the rod, the lugs having sharp protruding parts for engaging into the wall of the article to be removed. The protruding parts are directed away from each other if the article to be removed has to be engaged from the inside and are directed towards each other if the article to be removed has to be engaged from the outside. Means are present to move the protruding part(s) of at least one lug towards and away from the protruding part(s) of the other lug to allow the apparatus to be brought into the correct position with respect to the article to be removed in an easy manner and to thereafter cause the protruding parts to engage the article firmly to remove it by rotating the apparatus.

O United States Patent 1 51 3,654,825 Moddemeuer et al. [45] Apr. 11,1972 [s41 APPARATUS FOR LOOSENING 2,481,024 9/1949 Kencht ..8I/9l THREADPROTECTORS FROM 3,094,022 6/1963 Young ..81/90 TUBULAR BODIES PrimaryExaminer-James L. Jones, Jr. [72] Inventors: Jan H. Moddemeiier, Heiloo;Dirk Attorney-Hall & Houghton Jogchum Ziilstra, Djakarta, both ofNetherlands [57] ABSTRACT [73] Assignee: Hoogovens Delfstoffen N.V.,ljmuiden, An apparatus for removing substantially hollow articles fromNetherlands other articles into which or around which they are clamped,the article to be removed bein mainl s mmetrical around an [22] Wed:1970 axis and the surface of the othir articl e 0 which it is clamped[2i] Appl. No.: 17,372 also being symmetrical with respect to an axis sothat the removing is mainly possible by rotation. The apparatuscomprises a rod with two lugs at a distance from each other alongForeign Application Priority Data the rod, the lugs having sharpprotruding parts for engaging Mar. 1 1 1967 Netherlands ..69 03768 Wallarticle be rbmmd- The Pmmding P are directed away from each other if thearticle to be removed 52 US. Cl .;...8l/72 has be engaged mm the insideand are dbbcied Wards s 1 1m. (:1 ..B25b 13/48 each ifbe ankle be 'bmmdhas be engaged fmm [58] Field of Search ..81/71 72 53.2 155- (miside-Means are Presnt Pmmding Part) 279/15 6 5. 269748 of at least one lugtowards and away from the protruding part(s) of the other lug to allowthe apparatus to be brought [56] References Cited into the correctposition with respect to the article to be removed in an easy manner andto thereafter cause the UNITED STATES PATENTS protruding parts to engagethe article firmly to remove it by rotating the apparatus. 2,542,7132/1951 Schupbach ....81/72 Kinsey ..81/72 5 Claims, 5 Drawing FiguresPATENTEBAPR 11 I972 3,654,825

SHEEIlUFZ INVENTORJ ATTORNEY PATENTEDAPR 11 I972 3,654,825

SHEET 2 OF 2 BY 7%! WW ATTORNEY APPARATUS FOR LOOSENIN G THREADPROTECTORS FROM TUBULAR BODIES This invention relates to improvements inapparatus for removing a hollow article which is substantiallysymmetrical with respect to an axis and which is in rigid engagementwith a wall of a second article, said wall being also symmetrical withrespect to an axis, particularly for loosening a protector from a drilltube used when making drill holes in the soil for propecting or makingwells for hydrocarbons.

In making such drill holes the drill tubes made of high quality steelare connected mutually by threaded ends. The tubes have on one end outerthread being somewhat conical and often having a rounded thread profile,and at the other end the tubes have inner thread, also somewhat conicalwith rounded profile. As the threaded parts have to suffice severerequirements of accuracy and as there is a real danger that suchthreaded parts will be damaged machanically or in other manner duringtransport, storing and manupulation, it is usual to provide such tubesat the outer ends with separate protectors. Such protectors are sleeveswith outer or inner thread. Usually the quality of the steel from whichthey are made is lower than the quality of the steel of the tubes.

When the drill tubes have to be mutually connected the protectors areremoved. It appears that often such protectors cause difficulties inremoving because they are clamped too rigidly to the drill tubes, forinstance by some oxidation. They sometimes are turned into or on thedrill tube ends so as to be too rigidly connected thereto, which isparticularly possible because the threaded parts are often a littleconical in shape, or there is too rigid clamping by shockwise loadsduring transport, shipping and so on, so that they become more rigidlyconnected to the tubes than at the moment of applying the protectors tothe tubes.

Protectors engaging around the tube end do not cause so manydifficulties in removing as protectors engaging into a tube end. Outerprotectors may easily be removed by chain spanners or wrenches or thelike, but these require usually considerable space around the drill tubewhen applying or removing such protectors. Inner protectors are oftenconnected to the drill tube so rigidly that they need flame cutting tobe removed, so that the protector is thereby divided into parts and thusis no more suited for repeated use. In such flame cutting it oftenhappens that the inner screw-threaded part of the drill tube is damaged.Moreover such method takes much time and is expensive.

The present invention aims at obtaining an apparatus for the purposedescribed which is simple, allows the protectors to be removed easilyand without damage and thus allows the protectors to be used severaltimes. The drill tubes are not damaged in their vulnerable screwthreadedparts and the removing of the protectors becomes cheap and does not takemuch time.

In view of the above such an apparatus according to the inventioncomprises a rod having two lugs extending essentially in the samedirection transverse to the rod, said lugs each being provided with oneor more sharp protruding parts being positioned essentially in the sameline parallel to the rod, at least one of the sharp protruding partsbeing movable so as to vary the distance between the protruding parts ofthe two lugs to have the sharp protruding parts penetrate the wall ofthe article to be removed. The rod is suited for giving considerabletorque on the protector to be removed without the need to apply highforces to said rod because it could be long or even elongated byextension parts.

It has appeared that the sharp protruding parts do not damage theprotectors to such an extent that they could not be used several times.Moreover it appears that the forces applied when the sharp protrudingparts penetrate into the protector do not cause deformations thereofwhich could make removal more difficult.

The invention will now be explained in more detail with reference to theenclosed drawings, which give two preferred embodiments of apparatusaccording to the invention. In said drawings:

FIG. 1 shows an inner protector in a drill tube;

FIG. 2 shows on a larger scale an apparatus according to the invention,partly in section, according to a first preferred embodiment;

FIG. 3 shows a section according to line Ill-III in FIG. 2;

FIG. 4 shows a device according to the invention in a second preferredembodiment in side view; and

FIG. 5 shows this device in a view from above as seen in FIG. 4.

In FIG. 1 reference numeral 1 shows the end of a drill tube, which atthis end has an inner threaded part 2 being somewhat conicallyconverging from the free end. For protecting this screwthreaded part aprotector 3 is screwed into this end of the tube, said protector havingan outwardly protruding edge or flange 4 for protecting the end face ofthe tube.

An outer protector is provided at the other end of the tube 1 and thisis not shown. The tube 1 at said other end has an outer screwthreadedpart and this usually has the same diameter as the screwthreaded part 2,so that at that other end the tube 1 is provided with a part of smallerdiameter to take up such screwthread. This outer screwthread is alsosomewhat conical and is converging somewhat in a direction away from theconcerning end of the tube. Thus fully identical drill tubes may beconnected by screwing one end of one tube into an end of another tube.

FIGS. 2 and 3 show the first embodiment of an apparatus according to theinvention suited only for removing inner protectors as shown in FIG. 1,but this apparatus could easily be varied to be suited for removingouter protectors or for removing both inner and outer protectors.

In FIG. 2 reference numeral 5 indicates a rod which could be rectangularin cross-section, the left end of which being shown in shortened mannerserving as a handgrip for rotating by lever action. Two lugs 6 and 7extend from the rod and have a mutual distance which is somewhat smallerthan the inner diameter of the protector 3. In lug 6 there is ascrewthreaded pin 8 from steel, which is hard or which is hardened fullyor at the sharp conical pointed end only. This pin engages in ascrewthreaded bore of lug 6 and is easily displaceable longitudinallytherein to be adjusted in position or to be replaced. Lug 7 is providedclose to one free end of the rod 5 and is provided with a recess 9 nearits free end, said recess 9 being bridged by a pivot pin 10 extendingthroughout the lug 7 and the adjacent part of the rod 5 and being keptaxially in position by split pins.

Recess 9 is in part enclosed by an abutment part 11 and a pawl 12 isfreely rotatable about pin 10 between two positions one being shown inFIG. 3 in full lines and the other being shown diagrammatically by adotted line being inclined downwardly. In the position shown in fulllines in FIG. 3 the pawl 12 engages the abutment 11 and in this positiona hard pin 13 with a sharp pointed end screwed into a screwthreaded borein'pawl 12 takes up a position in which it has the same axis as the pin8 in lug 6. In this position the sharp points of pins 8 and 13 are asfar remote as possible.

To loosen and remove protector 3 from tube 1 (FIG. 1) the rod 5 is movedtowards this protector and assuming that rod 1 is in a horizontalposition, the rod takes up a horizontal position perpendicular to theaxis of rod 1. In this mutual position the lugs 6 and 7 are introducedinto the protector until the rod 5 abuts the end face of the flange 4 ofthe protector to the left and to the right of the lugs, so that also theextended end part of the rod 5 contacts this end face. During thisintroduction of the lugs the pawl 12 hangs downwardly by its own weightat an angle of about 45 to the horizontal according to the dotted linein FIG. 3 and this inclination is in the same direction as the directioninto which the apparatus has to be rotated to loosen the protector. Soin the present case it is assumed that the screwthread 2 is left-handed.If the screwthread 2 is righthanded the abutment 11 should be at theother side of pawl 12 and the pawl 12 should be able to turn into theother direction by its own weight. Of course the rod 5 will not alwaysbe positioned accurately with its centerline intersecting the axis oftube 1, but will be introduced in such a way that, if

desired after being lowered somewhat, the sharp points of pins 8 and 13contact the inner wall of the protector.

Now rod 5 is rotated into the direction in which the protector 3 has tobe loosened. This entrains that first the wall of the protector willcause the sharp point of pin 13 to rotate anticlockwise as seen in FIG.3 so that the sharp point of pin 13 penetrates into the inner wall ofthe protector and by the reaction force the sharp point of pin 8 willpenetrate an opposite part of the inner wall of the protector. Thispenetration goes on until the forces counteracting it become so highthat the protector is loosened on further rotation of rod 5. Pawl 12could turn back into contact with abutment 11 during this penetration,but the torque needed to loosen the protector could be such that theprotector begins to turn loose before this position is obtained. If pawl12 reaches abutment 11, pins 8 and 13 are in line diametrically oppositeeach other.

In the embodiment of FIGS. 4and 5 the rod 5, which could be hollow forlarger dimensions of protectors to be removed, has a lug 14 weldedthereto. This lug has two protruding parts 15. and 16 secured togetherand to said lug by bolts 17 and each having teeth 18. Said teeth arepositioned with their free ends in a curved path. The parts and 16 areof steel, and the free ends of the teeth are hardened or the parts 15and 16 are fully made of hard steel.

At some distance from this lug 14, which could be positioned near oneend of rod 5, there is a rectangular sleeve 19 entirely surrounding rod5 and taking up in and along its lower face as seen in FIG. 4 a separateclamping plate 20; The top face thereof is knurled or otherwiseroughened and the underface of the rod 5 is also roughened along part ofits length in this zone. Both ends 21 of the plate 20 are hookeddownwardly to prevent its sliding out of sleeve 19. A handgrip 22 has ascrewthreaded end 23 fitting into a screwthreaded bore in sleeve 19.Thus, sleeve19 could be firmly secured to red 5 or loosened therefromfor sliding along this rod.

On the other-face of sleeve 19, the top face of FIG. 4, there is a seatwasher 24 welded to the sleeve. It has two upstanding ridges 25 eachcovering an angle as seen from the center of about 90..

An upstanding, mainly conical lug 26 is rotatable and slidable around aspindle 27, which is welded to washer 24 and is centrally positionedtherein. This spindle has a helical compression spring 28 having a nut29 as'a seat on top and pushing the lug 26 downwardly. The lug 26carries a toothed block 30 of hard, steel or with hardened teeth 32,bolted at 31 to lug 26 and having teeth 32 positioned mutually in convexpattern as seen in FIG. 5.

The operation is as follows:

For removing internal protectors from tubes the rod 5 is positioned onthe end face of the protector so that the lugs 14 and 26 enter theprotector. To allow this the lug 26 is turned away from the position ofFIG. 5 so that the teeth 32 are closer to the teeth 18 of lug 14 than inthe position shown in FIGS. 4 and This turning of lug 26 could takeplace by gravity with the rod 5 in a horizontal position, as the lug isnot in equilibrium in view of the protruding tooth block 30, but if thespring 28 prevents this in view of the friction of the lug 26 withrespect to the washer 24 the lug could. be turned by hand. Anotherpossibility is to embody the helical spring 28 as a torsional spring bysecuring its ends to the nut 29 and to the lug 26 respectively, so thatthis spring tends to move the'lug 26 out of the position of the drawingsand into the lowermost position as possible in F IG. 5, in which theblock 30 is in contact with the end of the lower ridge 25. The bar 5 isintroduced or moved sideways after introduction in such a way that boththe teeth 18 and the teeth 32 contact the inner wall of the protector tobe removed. Thereupon the bar 5 is rotated in the sense in which theprotector is loosened and this will entrain that first the teeth 32 withthe lug 26 will rotate back to a position in which the block 30 ispositioned more radially or fully with respect to the protector, duringwhich rotation the distance between the teeth 32 and the teeth 18becomes larger, entraining that these teeth penetrate into the innerwall of e protector so that on further turning of the bar 5 theprotector is rotated with the bar and is thus loosened from its tube.

After rotating the handgrip 22 to loosen the plate 20 it is possible tomove the sleeve 19 along the bar 5 to adapt the distance between thissleeve and the lug 14 to different diameters of protectors. Moreover, itis thus possible to adapt the distance between the lugs to situations inwhich an outer protector has to be removed. If this has to be done thelug 26 is easily lifted by hand from the washer 24 against the action ofthe spring 28 and the lug is thereupon rotated about after which it isin a position, in which the tooth block 30 is in the opposite spacebetween the ridges 25 than shown in FIG. 5, the teeth 32 thus beingdirected towards the lug 14. Now the device is adapted to operate on the.outside of a body to be removed such as an outer protector bycooperation of the teeth 32 with the teeth 18 of lug 14.

If will be clear that the invention could be embodied in different waysdeviating from what has been described above but within the scope of thefollowing claims.

We claim:

1. Apparatus particularly for loosening a protector from a drill tubeused in drill holes for prospecting for hydrocarbons, said apparatuscomprising a rod having two lugs provided with sharp protruding parts,and means for moving at least one of the sharp protruding parts so as tovary the distance therebetween, said last named means including a pivotpin connected to one of the lugs and extending in the main direction ofsaid lug, and a member rotatable around the axis of said pin andprovided with one or more of said sharp protruding parts, an abutmentbeing provided on or adjacent to the lug for limiting the rotation ofsaid member such that its rotation is limited to a position where thesharp protruding parts of the two lugs are substantially in line withone another parallel to the rod.

2. Apparatus according to claiml, characterized in that the other lughas sharp protruding parts directed in opposite directions aboutparallel to the rod and that the said rotatable member cooperates withmeans-to be arranged in two mutually different positions, in one ofwhich its sharp protruding parts are directed towards the said other lugand in the other of which its protruding parts are directed away fromsaid other lug to adapt the apparatus for removing both external andinternal protectors or other hollow articles.

3. Apparatus according to claim 1, characterized in that the rotatablemember is urged by. spring action into a position away from the positionin contact with the abutment.

4. Apparatus according to claim 1, characterized in that one of the lugsis provided on a sleeve surrounding the rod and slidable with respectthereto, said sleeve being provided with means to be easily detachablysecurable in desired positions to the rod.

5. Apparatus according to claim 1, characterized in that the protrudingparts are adjustable with respect to the lugs in longitudinal directionof the rod and are preferably fully detachable and replaceable from andwith respect to the lugs.

1. Apparatus particularly for loosening a protector from a drill tubeused in drill holes for prospecting for hydrocarbons, said apparatuscomprising a rod having two lugs provided with sharp protruding parts,and means for moving at least one of the sharp protruding parts so as tovary the distance therebetween, said last named Means including a pivotpin connected to one of the lugs and extending in the main direction ofsaid lug, and a member rotatable around the axis of said pin andprovided with one or more of said sharp protruding parts, an abutmentbeing provided on or adjacent to the lug for limiting the rotation ofsaid member such that its rotation is limited to a position where thesharp protruding parts of the two lugs are substantially in line withone another parallel to the rod.
 2. Apparatus according to claim 1,characterized in that the other lug has sharp protruding parts directedin opposite directions about parallel to the rod and that the saidrotatable member cooperates with means to be arranged in two mutuallydifferent positions, in one of which its sharp protruding parts aredirected towards the said other lug and in the other of which itsprotruding parts are directed away from said other lug to adapt theapparatus for removing both external and internal protectors or otherhollow articles.
 3. Apparatus according to claim 1, characterized inthat the rotatable member is urged by spring action into a position awayfrom the position in contact with the abutment.
 4. Apparatus accordingto claim 1, characterized in that one of the lugs is provided on asleeve surrounding the rod and slidable with respect thereto, saidsleeve being provided with means to be easily detachably securable indesired positions to the rod.
 5. Apparatus according to claim 1,characterized in that the protruding parts are adjustable with respectto the lugs in longitudinal direction of the rod and are preferablyfully detachable and replaceable from and with respect to the lugs.